1954 AJS Model 20 500 Technical Analysis & Specification Breakdown
At the heart of the 1954 AJS Model 20 500 allround motorcycle, AJS features a 498 cc (30.4 cu in) air-cooled twin, four-stroke configuration. In factory specification, peak output is rated at 20 HP (14.6 kW) at 6,800 rpm, transferring power to the rear wheel through a 4-speed gearbox and chain final drive. With a specific output of 40.2 HP per liter, the engine character is prioritizing low-RPM tractability, mechanical longevity and relaxed throttle response over peak redline numbers.
On the scales, the Model 20 500 measures 178 kg (392 lbs) dry, translating to a power-to-weight ratio of 0.11 HP/kg (8.9 kg per horsepower). The 13.5-liter (3.6 US gal) fuel tank supports practical everyday commuting and weekend road stints, while factory top speed is listed at 137 km/h (85 mph).
Within MotoLibrary's AJS archive, this model family spans 11 indexed model years from 1949 to 1959, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Power
Compare engine output with similar motorcycles if acceleration, highway use or two-up riding matters.
Weight
Compare weight carefully because it affects low-speed handling, parking and confidence.
Fuel Capacity
Fuel capacity helps estimate touring range and how often you may need to stop.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.
